yesterday i was driving and it was wet out so i decided to get the rpms up to 7500 and when i let off the gas the car backfired like crazy , all the way down to idle then sounded like it was running super rich or on 1 rotor or something and i could barely even move anywhere , i thought it was a stuck open injector because the guy i got the car from gave me new injectors when i got the car and said it flooded out sometimes ? Also When My car messed up i could turn the car on without the fuel pump connected and it would run , but like **** ofcourse and it wouldnt die out unless i gas'd it.. regardless i turned the key to the on position and looked under the hood and sounded like an injector vibrating or whatever so i pulled my manifold off and replaced the lower injectors , turned the car to the on position to see if they leaked after i installed them (yes i am a first timer) and they didnt seem to leak , i Put everything back together and its doing the same thing is was doing before i changed the TWO Lower Injectors . Mind you these injectors are from Rock Auto brand new for like 130$ a piece (Via Injector Part Number). Made sure to lube the o rings too , i just dont see what it could be ? Going to Pull the codes later on today and try and figure this out , This car is my daily and i really need it on the road asap :[

 

the symptoms your describing sound like a tired motor, and running with the fuel pump unhooked can happen, cause theres still pressure in the lines. I would definitely do do a compression check. or you may even have bad new injectors, usually doesn't happen, but can

 

compression test.

 

This happened to me once at a drift event with my S5 N/A. I blew most of the vacuum hoses off of their nipples.
Check them, if they're on, do a compression test.

 

they must have been extremely loose since the n/a can barely manage 1-2psi of resonant pressure.

 

I don't think they were. I think the throttle transitions just caused some A/F mixture to surge back into the intake and it ignited.
A lot of WOT and heavy load that day.
It was great!

 

so i tried to check my codes and ended up killing the cel light somehow ? maybe i killed the ecu .. going to get a new ecu and do a compression check soon ..

 

Could be just the light bulb. You could also use the code checker light used for the S4 and use it on an S5. Cost about a few bucks to make. The check connector near the lead coil w/four wires is where you plug in the code checker light.

 

http://2ndgenrx7.freeservers.com/error%20codes.html

 

Have you checked to see if the TPS is stuck in? I had this happen once and the injectors were pumping fuel in like crazy without any throttle input so it ran like complete crap. I swapped the TPS out with one that actually functioned properly and the car ran fine after. Something to consider before dropping money on other things.

 

turns out the vaccum for the tps was clogged .. all back to normal ! :]

 

"Normally" there is no vacuum to the TPS.

 

any guess on why my car still hesitates to go past 6500 under load but just WOT at idle i can redline .. any suggestion would really be helpful as you can see i need a rotaries for dummies book .

 

Are you redlining while in neutral or in gear?

 

Redlined in gear and in neutral , I believe that wouldn't really make a difference any ways regardless in gear or neutral the car isn't under any load .


Is there anyway to lower Idle , my car is stock s5 6 port na and idles at 1.8 -2k rpms

 

If you're redlining while driving then it is under load. Redline while in neutral and you're not under load. Check the throttle cable for being too tight for starters.

 

ok so it took 3 seconds and a brain to lower my idle by adjusting the throttle cable nut , now i realized i lost the clip to hold the throttle cable tight when i put my intake manifold back on from swapping out injectors .. i got it idle'n at 800 now but still leans out or gets too rich at 6500 rpm helpppp